In the manufacture of fluorescent lamps, the amount of phosphor required to coat a given size lamp depends greatly on the particle size of the phosphor that is being used. In general, the smaller the particle size the less amount of phosphor that is required to give a uniform coating and generate the greatest amount of light output which results in cost saving in lamp manufacture. In addition, modern fluorescent lamp manufacture uses multiple layer coating technology with less expensive halophosphate phosphor as a base layer, then overcoat with a skin layer of high lumen, high color rendition rare earth containing phosphor. There is a significant advantage in that this skin layer of rare earth phosphor is of small particle size which not only gives uniform coating without pin holes but also cold coat thinner than regular large particle size phosphor. This results in both a reduced lamp manufacture cost and high lamp brightness with better color rendition.